EP0371988B1 - Metal spraying apparatus - Google Patents
Metal spraying apparatus Download PDFInfo
- Publication number
- EP0371988B1 EP0371988B1 EP88906458A EP88906458A EP0371988B1 EP 0371988 B1 EP0371988 B1 EP 0371988B1 EP 88906458 A EP88906458 A EP 88906458A EP 88906458 A EP88906458 A EP 88906458A EP 0371988 B1 EP0371988 B1 EP 0371988B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- coolant
- wires
- guide tubes
- wire
- spaces
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
- B05B7/16—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed
- B05B7/22—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed electrically, magnetically or electromagnetically, e.g. by arc
- B05B7/222—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed electrically, magnetically or electromagnetically, e.g. by arc using an arc
- B05B7/224—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed electrically, magnetically or electromagnetically, e.g. by arc using an arc the material having originally the shape of a wire, rod or the like
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
- C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
- C23C4/131—Wire arc spraying
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
- B05B1/28—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means with integral means for shielding the discharged liquid or other fluent material, e.g. to limit area of spray; with integral means for catching drips or collecting surplus liquid or other fluent material
Definitions
- This invention relates to a hand held gun for spraying metal in a forward direction according to the preamble of claim 1 (see US-A-4 512 513).
- Such spray guns are commonly referred to in the art as arc spray guns or, for brevity, "arc guns.”
- arc spray metallizing guns are well known and have been suitable for many purposes, experience has shown that they are not practical for certain tasks.
- the spray rate of present day arc guns is such that it is too labor-intensive to use them for spraying large structures such as bridges.
- Metallized spraying of such structures is a very desirable technique since it is possible to spray a zinc coating which will give cathodic protection which is more effective and more durable than conventional painting of such structures.
- US 4 512 513 discloses an arc metal spray apparatus and a method to provide coatings on objects.
- This apparatus comprises a base housing with driving, controlling and feeding means and a portable head.
- An atomizing gas nozzle provides the transport of metal droplets thereby also becoming a coolant.
- One object of the invention is to provide an arc spray gun which is suitable for large scale projects and is capable of delivering a higher spray rate than existing devices of this type.
- Another object is to provide an arc spray gun which is relatively lightweight and is easily manipulated, yet is also able to deliver a metallizing spray at a high rate.
- Another object is to provide an arc spray gun which is effective, relatively uncomplicated and easily maintained.
- the first area of improvement to such an arc spray gun is the inclusion of means for cooling the electrical conductor by circulating a stream of coolant liquid along the electrical conductor.
- a second improvement relates to a gun where guide tubes are located in forwardly convergent bores in an insulating gun head. The walls of the guide tubes are spaced radially from the tubes to provide spaces for coolant fluid around the guide tubes.
- Wire feed rolls have their axes perpendicular relative to the wire guides and at an obtuse angle relative to each other.
- each of these fittings has an internal coolant passage which is in communication with one of the coolant fluid spaces within the head.
- the head may have a coolant passage which extends between the coolant fluid spaces so that a stream of coolant fluid may flow serially through the coolant fluid spaces.
- the guide tubes extend through the conductive fittings and to provide compression fittings which are operable to affix the guide tubes to the conductive fittings.
- compression fittings are releasable to permit longitudinal adjustment movement of the guide tubes, and the compression fittings include cap nuts which are threadedly connected to the conductive fittings.
- the wire feed means includes a motor connected to a main drive shaft which has drive gear means mounted thereon for rotation therewith.
- the drive gear means includes a first set of drive gear teeth and a second set of drive gear teeth.
- a first wire feed wheel is connected to and driven by a first driven gear which has its teeth engaged with the first set of drive gear teeth.
- a second wire feed wheel is connected to and driven by a second driven gear which has its teeth engaged with the second set of drive gear teeth.
- the two driven gears are located on opposite sides of the shaft and the first and second sets of drive gear teeth face in opposite axial directions on the main drive shaft so that the driven gears and their respective feed wheels are rotated in directions which drive the wires forwardly in the wire guide means.
- the driven gears and feed wheels rotatable about axes which, in plan view, lie at an obtuse angle relative to each other. Also, these rotational axes lie perpendicular to the guide tubes.
- Fig. 1 is a partially sectioned perspective view of a metallizing gun constructed according to the invention.
- Fig. 2 is a plan view of the apparatus of Fig. 1.
- Fig. 3 is a partially sectioned elevational view of the gun of Fig. 1.
- Fig. 4 is a front view showing only a forward portion of the gun of Fig. 1.
- Fig. 5 is a sectional view as seen along the line 5-5 in Fig. 2.
- Fig. 6 is a sectional view as seen along the line 6-6 in Fig. 2.
- Fig. 7 is a plan view of the insulating body of the gun of Fig. 1.
- Fig. 8 is a sectional view as seen along the line 8-8 in Fig. 7 to show the passages for spray shaping air.
- Fig. 9 is a sectional view as seen along the line 9-9 of Fig. 7 to show the passages for atomizing air.
- Fig. 10 is a sectional view of a modified type of spray shaping and shielding means for a metallizing gun.
- the gun has a main body 2 mounted on the upper end of a handle 4.
- a conventional hand-operated switch actuator 5 is mounted on the handle to deactivate the apparatus when the operator's grip is released.
- a head 6 is mounted on the forward end of the body 2 and is arranged so that metal sprayed by the gun is discharged in a forward direction represented by the arrow 8.
- Wires 10 and 12 are fed in a forward direction by a pair of feed wheels, one of which is shown at 14, into guide tubes, one of which is shown at 16.
- the wires pass through the head 6 and emerge at tips 18 and 20 which constitute the forward ends of the guide tubes.
- the wires are on converging paths and they are maintained at different electrical potentials so that an arc will be formed between the wires to heat them and melt their forward ends.
- the wire material thus molten is impinged by a high velocity stream of atomizing air from the air outlet 22 at the forward end of the head 6, thus breaking the molten metal into small droplets and propelling them as a spray for deposition on a surface.
- An airborne stream of molten metal droplets is propelled forwardly until it strikes the surface of the workpiece which is being sprayed.
- a shield 27 is mounted on the head 6 in order to surround the area of the electric arc.
- the head 6 is formed of an electrically insulating plastic material. It has a forward truncated conical portion 29, a cylindrical portion 31 which is externally threaded, and a rear portion which, as shown in Fig. 5, is attached by screws 33 to the main body 2. As shown in Fig. 1, a cap 35 is removably mounted on an unthreaded section of the cylindrical portion 31, and the shield 27 is threaded onto the portion 31. A pair of spray shaping nozzles 24 and 26 are affixed to the cap 35, and these nozzles direct converging streams of spray-shaping air into and downstream of the droplet-forming region. This produces a fan shaped spray. For convenience of illustration, the cap 35 is not shown in Figs. 2-5.
- An atomizing air source is connected to the gun by a conduit 28, and spray-shaping air for the nozzles 24 and 26 is supplied by a conduit 30.
- a coolant supply unit sends a liquid or gaseous coolant to the gun through a conduit 32, and this unit receives a return flow of the coolant fluid from the conduit 34.
- a conventional electric power source is connected to a motor in handle 4 by a cord (not shown), and the arc-generating electrical power source is connected to the gun by braided copper conductors 36 and 38 which extend through the coolant conduits 32 and 34.
- Figs. 2, 3 and 6 The means for guiding and feeding the wires is best shown in Figs. 2, 3 and 6. Referring to Fig. 2, it will be seen that the wires are guided lengthwise along two axes which are mutually convergent in a forward direction so that, in the area of the electric arc, the forward ends of the wire will lie proximate to each other.
- each wire guide tube 16 receives the wire 10 at its rear end and releases the wire at a tip 18 at the forward end of the guide tube.
- the guide tube extends concentrically through a bore in the head 6, and this bore has sections of three different diameters.
- the small diameter forward portion 40 of the bore snugly receives the guide tube and is sealed thereagainst by means of an O-ring 42.
- the intermediate portion 44 of the bore is somewhat larger than the guide tube in order to provide a radial spacing and a cylindrical passage for coolant fluid as will be later described.
- the large diameter rear portion 46 has a diameter corresponding approximately to the outside diameter of a cylindrical extension 48 of a fitting 50, the functions of which will be subsequently described.
- An O-ring 52 provides a seal between the bore portion 46 and extension 48.
- the fitting 50 is formed of an electrically conductive material such as brass, and it is mounted on the head 6 by a screw 53.
- the fitting 50 has a horizontal bore 54 which is intersected by a vertical bore 56.
- the forward portion of bore 54 is larger than the guide tube 16, thus providing a cylindrical space which is an extension of and communicates with the cylindrical coolant fluid passage in the head 6.
- the rear end of the bore 54 has a diameter approximately equal to the outside diameter of the guide tube 16, and this lies within a fitting portion 58 which is externally threaded to receive the internal threads of a cap nut 60.
- the principal electrical connection between the fitting 50 and the guide tube 16 is in the area or zone within the fitting portion.
- the coolant passage around the guide tube is in the area between this electrical connection and the arc zone at the front of the gun.
- a brass compression ring 62 is located within the cap nut.
- the compression fitting comprising the cap nut 60 and compression ring 62 is usually tightened to affix the guide tube 16 to the fitting 50. However, loosening of the cap nut 60 releases the compression fitting to permit longitudinal and/or rotational adjustment movement of the guide tube 16.
- the rear end of the tube 16 is received in an opening formed in a flange 39 on the main body 2.
- FIG. 3 only shows one guide tube 16, it will be understood that the guide tube 16A on the right side of the gun is constructed and mounted in a similar manner.
- each wire at the gun moves in an unbent linear path to the arc zone.
- Fig. 2 where it will be noted that the rotational axes of the feed wheels 14 and 14A, coincident with the section line 6-6, lie at an obtuse angle relative to each other, and they also lie perpendicularly to the linear paths established by the guide tubes 16 and 16A.
- the cooling means for the gun includes a fluid circulating unit which is connected to the gun by the supply and return conduits 32 and 34 respectively.
- the supply conduit is affixed to a tube 64 which is integral with the fitting 50.
- liquid or other coolant fluid from the supply conduit 32 will flow in the direction of arrow 66 into the cylindrical space which extends around and longitudinally of the guide tube 16.
- the fluid exits this space via a transverse bore 68 which can also be seen in Figs. 4 and 5.
- an arrow 70 indicates the direction of coolant fluid movement in this area.
- the right side of the gun has a fitting 50A shown in Fig. 2 which is identical to the fitting 50 and also provides a cylindrical fluid passage around the corresponding guide tube 16A. Therefore, the coolant fluid which passes transversely through the bore 68 into the coolant space around the tube 16A then flows rearwardly around the tube 16A until it arrives at the vertical bore which corresponds with the bore 56 shown in Fig. 3. From this point, the coolant fluid flows downwardly into the return conduit 34 shown in Fig. 1 which then carries the fluid to the coolant circulator.
- the circulating unit can include a heat exchanger which is cooled by air, water, or a refrigeration system.
- the coolant fluid serves the important function of cooling the electrical conductors 36 and 38 which provide the arc-forming electrical potential difference between the tips 18 and 20 and their respective wires.
- these electrical conductors are elongated braided copper wires and they have a generally rectangular transverse cross section.
- the electrical conductor 36 is electrically connected to the tube 64 of fittings 50 by silver soldering at 72.
- the coolant is circulated through the conduits 32 and 34 in order to cool the electrical conductors which, if uncooled, would overheat due to the very high current required for high spray rates.
- the body 2 and head 6 have a series of internal passages which carry the atomizing air and the spray shaping air to the outlets 22, 24 and 26.
- the passages for the atomizing air are best shown in Figs 5, 7 and 9. Referring to Figs. 7 and 9, it will be seen that the atomizing air initially moves through a horizontal bore 74 to a vertical bore 76 which has a plug 78 obstructing its upper end, and thence through a horizontal bore 79, the forward end of which terminates at an O-ring seat 80. As shown in Fig. 5, seat 80 aligns with a similar O-ring seat 82 formed in the head 6. From this area a bore 84 extends forwardly to the atomizing air outlet 22. As shown in Fig. 4, this outlet preferably has an oval shape and it is located centrally between the guide tips 18 and 20.
- the passages for the spray shaping air can be seen best in Figs. 5, 7 and 8. This air passes sequentially through the horizontal bore 86, a vertical bore 88 which is capped by a plug 90, and a pair of horizontal bores 92 and 92A. The air then passes into the diverging bores 96 and 96A which are shown in Fig. 5. Finally, the spray shaping air is carried by the spray-shaping nozzle tubes 24 and 26 which have forwardly inclined mutually convergent axes for shaping the spray which emerges from the gun.
- the wire supply is preferably of the push-pull type wherein the wire comes from a stationary supply which is spaced from the spray gun.
- the wire supply has pusher rolls 97 which engage the wires 10 and 12 and drive them toward the gun.
- a flexible wire guiding conduit 99 has its opposite ends affixed to the wire supply and to the gun so that it acts in some respects like a Boden wire system.
- the wire feed rolls 97 connected to motor 101 at the wire supply are operated, the wire is pushed forwardly to the feed rolls 14 which pull the wire and deliver it toward the head.
- the effect of the pusher rolls is to apply compressive forces to the wires within the wire guiding conduits, and also to apply tensile forces to the conduits 99 themselves.
- the use of pusher rolls reduces the demands on the wire feeding motor in the gun handle, thus making it possible to use a very lightweight motor in the gun.
- the wires 10 and 12 are fed along their respective longitudinal axes by two substantially identical mechanisms which are mirror images of each other.
- the wire 10 is frictionally engaged between the feed wheel 14 and an idler wheel 100 which is mounted on a swinging plate 102.
- the plate 102 is pivotally mounted on a screw 104 and it is biased in a clockwise direction by a compression spring 105.
- the biasing force is adjustable by manually rotating the knurled adjustment knob 106 which is integral with a spring-supporting pin 108 which is threaded into a mounting plate 109 on the body 2.
- rotation of the adjustment knob 106 will change the degree of compression of the spring 105, thus changing the loading force which the idler wheel 100 exerts on the wire 10 to hold the wire against the feed wheel 14.
- a small electric motor is housed within the handle 4. This motor rotationally drives a vertical shaft 110 which is mounted on ball bearing assemblies 112 and 114, and it carries a lower bevel gear 116 and an upper bevel gear 118.
- the left feed wheel 14 is mounted on a shaft 120 which is rotationally supported on a pair of ball bearing units 122 and 124. At the right end of the shaft, there is a bevel gear 126 with teeth which mesh with the teeth of the lower bevel gear 116 on the motor-driven shaft 110. Thus, the upper wire-engaging portion of the wheel 14 is rotated in a forward direction to feed the wire through the guide tube and to the fusion area.
- the right feed wheel 14A must also be driven so that its upper wire-engaging surface is moving in a forward direction. Such motion is achieved by mounting the feed wheel 14A on a shaft 128 which has, at its left end, a bevel gear 130 with teeth which mesh with the teeth of the upper bevel gear 118.
- the shaft 128 is rotationally supported by the ball bearing units 132 and 134.
- the rotational axes of the shafts 120 and 128 are at an obtuse angle relative to each other. These rotational axes are perpendicular to their respective wires and guide tubes.
- the wire-engaging circumferences of the feed wheels 14 and 14A are electrically insulated from the shafts 120 and 128. Such insulation may be provided, for example, by providing the wheels with internally threaded plastic hubs which are threaded onto the respective shafts. Metal rings which contact the wires are affixed to the plastic hubs.
- Figs. 1-9 differs slightly from the version shown in Figs. 2-9.
- the upper surface of head 6 has a raised central portion
- the body 2 has an upper surface which is flat except for a raised forward portion
- the swing plate has a rear extension which receives the pivot screw 104.
- the cone 27, cap 35 and spray-shaping nozzles 24 and 26 are removed from the head and replaced by an assembly, shown in Fig. 10, which includes a cone 136 and a shield 137. Air is introduced into the cone from the bores 96 and 96A. The resulting spray strikes a smaller area than the fan shaped spray, and a smoother coating is produced.
- the cone 136 has a circumferentially protruding flange at its base which is received in a corresponding recess on the internal surface of the spray shield 137.
- the invention is particularly advantageous because it provides a relatively small, easily manipulable gun capable of delivering a very high spray rate which, in some instances, can be as much as seven to eight times the spray rate normally achieved with existing lightweight handheld guns.
- a gun made according to the present invention weighs less than 1.25 kg (four and one half pounds). It has a length of approximately 20 cm (eight inches), a height of approximately 21.4 cm (eight and one half inches) including the handle, and a width of about 11.3 cm (four and one half inches).
- the conduits 32, 34 and cables 36, 38 are 24 m (seventy feet) long, and water is circulated through the conduits at a rate of 9 l/min (two gallons per minute).
- the temperature difference between the incoming and outgoing water is twenty-five degrees C.
- the electric power source delivered 1400 amperes at 50 volts, making it possible to spray aluminum wire of 0.3 cm (1/8 inch) diameter at a rate of 40 kg (80 pounds) per hour.
- the gun is capable of spraying wire having diameters from 0.15 to 0.3 cm (1/16 to 1/8 inch), and numerous metal compositions such as aluminum, zinc, steel, bronze, babbit and other alloys.
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Plasma & Fusion (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electromagnetism (AREA)
- Coating By Spraying Or Casting (AREA)
- Nozzles (AREA)
Abstract
Description
- This invention relates to a hand held gun for spraying metal in a forward direction according to the preamble of claim 1 (see US-A-4 512 513). Such spray guns are commonly referred to in the art as arc spray guns or, for brevity, "arc guns."
- Although arc spray metallizing guns are well known and have been suitable for many purposes, experience has shown that they are not practical for certain tasks. For example, the spray rate of present day arc guns is such that it is too labor-intensive to use them for spraying large structures such as bridges. Metallized spraying of such structures is a very desirable technique since it is possible to spray a zinc coating which will give cathodic protection which is more effective and more durable than conventional painting of such structures.
- US 4 512 513 discloses an arc metal spray apparatus and a method to provide coatings on objects. This apparatus comprises a base housing with driving, controlling and feeding means and a portable head. An atomizing gas nozzle provides the transport of metal droplets thereby also becoming a coolant.
- From US 3 312 566 an apparatus is known, which is provided for generating large quantities of small-diameter particles in short periods of time. The particles are generated by a plasma process in a cooled head-component.
- One object of the invention is to provide an arc spray gun which is suitable for large scale projects and is capable of delivering a higher spray rate than existing devices of this type.
- Another object is to provide an arc spray gun which is relatively lightweight and is easily manipulated, yet is also able to deliver a metallizing spray at a high rate.
- Another object is to provide an arc spray gun which is effective, relatively uncomplicated and easily maintained.
- The above mentioned objects are solved by a hand held gun for spraying metal in a forward direction according to claim 1.
- The first area of improvement to such an arc spray gun is the inclusion of means for cooling the electrical conductor by circulating a stream of coolant liquid along the electrical conductor. A second improvement relates to a gun where guide tubes are located in forwardly convergent bores in an insulating gun head. The walls of the guide tubes are spaced radially from the tubes to provide spaces for coolant fluid around the guide tubes.
- Another important feature of the invention, taken together with the cooling arrangement, is that the wires follow unbent linear paths through the gun, thus reducing energy consumption and facilitating high wire velocities. Wire feed rolls have their axes perpendicular relative to the wire guides and at an obtuse angle relative to each other.
- Preferably two electrically conductive fittings are affixed to opposite sides of the head. Each of these fittings has an internal coolant passage which is in communication with one of the coolant fluid spaces within the head. The head may have a coolant passage which extends between the coolant fluid spaces so that a stream of coolant fluid may flow serially through the coolant fluid spaces.
- It is also preferred to have the guide tubes extend through the conductive fittings and to provide compression fittings which are operable to affix the guide tubes to the conductive fittings. Such compression fittings are releasable to permit longitudinal adjustment movement of the guide tubes, and the compression fittings include cap nuts which are threadedly connected to the conductive fittings.
- The wire feed means includes a motor connected to a main drive shaft which has drive gear means mounted thereon for rotation therewith. The drive gear means includes a first set of drive gear teeth and a second set of drive gear teeth. A first wire feed wheel is connected to and driven by a first driven gear which has its teeth engaged with the first set of drive gear teeth. A second wire feed wheel is connected to and driven by a second driven gear which has its teeth engaged with the second set of drive gear teeth. The two driven gears are located on opposite sides of the shaft and the first and second sets of drive gear teeth face in opposite axial directions on the main drive shaft so that the driven gears and their respective feed wheels are rotated in directions which drive the wires forwardly in the wire guide means.
- Regarding the wire driving means, it is preferred to have the driven gears and feed wheels rotatable about axes which, in plan view, lie at an obtuse angle relative to each other.
Also, these rotational axes lie perpendicular to the guide tubes. - Fig. 1 is a partially sectioned perspective view of a metallizing gun constructed according to the invention.
- Fig. 2 is a plan view of the apparatus of Fig. 1.
- Fig. 3 is a partially sectioned elevational view of the gun of Fig. 1.
- Fig. 4 is a front view showing only a forward portion of the gun of Fig. 1.
- Fig. 5 is a sectional view as seen along the line 5-5 in Fig. 2.
- Fig. 6 is a sectional view as seen along the line 6-6 in Fig. 2.
- Fig. 7 is a plan view of the insulating body of the gun of Fig. 1.
- Fig. 8 is a sectional view as seen along the line 8-8 in Fig. 7 to show the passages for spray shaping air.
- Fig. 9 is a sectional view as seen along the line 9-9 of Fig. 7 to show the passages for atomizing air.
- Fig. 10 is a sectional view of a modified type of spray shaping and shielding means for a metallizing gun.
- Referring to Fig. 1, it will be seen that the gun has a
main body 2 mounted on the upper end of ahandle 4. A conventional hand-operatedswitch actuator 5 is mounted on the handle to deactivate the apparatus when the operator's grip is released. Ahead 6 is mounted on the forward end of thebody 2 and is arranged so that metal sprayed by the gun is discharged in a forward direction represented by thearrow 8. -
Wires head 6 and emerge attips air outlet 22 at the forward end of thehead 6, thus breaking the molten metal into small droplets and propelling them as a spray for deposition on a surface. An airborne stream of molten metal droplets is propelled forwardly until it strikes the surface of the workpiece which is being sprayed. To reduce the risk of eye damage, ashield 27 is mounted on thehead 6 in order to surround the area of the electric arc. - The
head 6 is formed of an electrically insulating plastic material. It has a forward truncatedconical portion 29, acylindrical portion 31 which is externally threaded, and a rear portion which, as shown in Fig. 5, is attached byscrews 33 to themain body 2. As shown in Fig. 1, acap 35 is removably mounted on an unthreaded section of thecylindrical portion 31, and theshield 27 is threaded onto theportion 31. A pair ofspray shaping nozzles cap 35, and these nozzles direct converging streams of spray-shaping air into and downstream of the droplet-forming region. This produces a fan shaped spray. For convenience of illustration, thecap 35 is not shown in Figs. 2-5. - Externally of the gun, there is a unit which supplies the fluids and electricity required for proper operation. An atomizing air source is connected to the gun by a
conduit 28, and spray-shaping air for thenozzles conduit 30. A coolant supply unit sends a liquid or gaseous coolant to the gun through aconduit 32, and this unit receives a return flow of the coolant fluid from theconduit 34. A conventional electric power source is connected to a motor inhandle 4 by a cord (not shown), and the arc-generating electrical power source is connected to the gun by braidedcopper conductors coolant conduits - The means for guiding and feeding the wires is best shown in Figs. 2, 3 and 6. Referring to Fig. 2, it will be seen that the wires are guided lengthwise along two axes which are mutually convergent in a forward direction so that, in the area of the electric arc, the forward ends of the wire will lie proximate to each other.
- Fig. 2, shows that each
wire guide tube 16 receives thewire 10 at its rear end and releases the wire at atip 18 at the forward end of the guide tube. The guide tube extends concentrically through a bore in thehead 6, and this bore has sections of three different diameters. The small diameterforward portion 40 of the bore snugly receives the guide tube and is sealed thereagainst by means of an O-ring 42. Theintermediate portion 44 of the bore is somewhat larger than the guide tube in order to provide a radial spacing and a cylindrical passage for coolant fluid as will be later described. The large diameterrear portion 46 has a diameter corresponding approximately to the outside diameter of acylindrical extension 48 of a fitting 50, the functions of which will be subsequently described. An O-ring 52 provides a seal between thebore portion 46 andextension 48. - The fitting 50 is formed of an electrically conductive material such as brass, and it is mounted on the
head 6 by ascrew 53. The fitting 50 has ahorizontal bore 54 which is intersected by avertical bore 56. The forward portion ofbore 54 is larger than theguide tube 16, thus providing a cylindrical space which is an extension of and communicates with the cylindrical coolant fluid passage in thehead 6. The rear end of thebore 54 has a diameter approximately equal to the outside diameter of theguide tube 16, and this lies within afitting portion 58 which is externally threaded to receive the internal threads of acap nut 60. The principal electrical connection between the fitting 50 and theguide tube 16 is in the area or zone within the fitting portion. Thus, it will be appreciated that the coolant passage around the guide tube is in the area between this electrical connection and the arc zone at the front of the gun. Abrass compression ring 62 is located within the cap nut. The compression fitting comprising thecap nut 60 andcompression ring 62 is usually tightened to affix theguide tube 16 to the fitting 50. However, loosening of thecap nut 60 releases the compression fitting to permit longitudinal and/or rotational adjustment movement of theguide tube 16. The rear end of thetube 16 is received in an opening formed in aflange 39 on themain body 2. - Although the illustration in Fig. 3 only shows one
guide tube 16, it will be understood that theguide tube 16A on the right side of the gun is constructed and mounted in a similar manner. - An important feature of the invention, when combined with the cooling means, is that each wire at the gun moves in an unbent linear path to the arc zone. This will be understood by reference to Fig. 2 where it will be noted that the rotational axes of the
feed wheels guide tubes - The cooling means for the gun includes a fluid circulating unit which is connected to the gun by the supply and return
conduits tube 64 which is integral with the fitting 50. Thus, liquid or other coolant fluid from thesupply conduit 32 will flow in the direction ofarrow 66 into the cylindrical space which extends around and longitudinally of theguide tube 16. The fluid exits this space via atransverse bore 68 which can also be seen in Figs. 4 and 5. In Fig. 4, anarrow 70 indicates the direction of coolant fluid movement in this area. - The right side of the gun has a fitting 50A shown in Fig. 2 which is identical to the fitting 50 and also provides a cylindrical fluid passage around the corresponding
guide tube 16A. Therefore, the coolant fluid which passes transversely through thebore 68 into the coolant space around thetube 16A then flows rearwardly around thetube 16A until it arrives at the vertical bore which corresponds with thebore 56 shown in Fig. 3. From this point, the coolant fluid flows downwardly into thereturn conduit 34 shown in Fig. 1 which then carries the fluid to the coolant circulator. The circulating unit can include a heat exchanger which is cooled by air, water, or a refrigeration system. - In addition to cooling the guide tubes in the head portion of the apparatus, the coolant fluid serves the important function of cooling the
electrical conductors tips electrical conductor 36 is electrically connected to thetube 64 offittings 50 by silver soldering at 72. The coolant is circulated through theconduits - The
body 2 andhead 6 have a series of internal passages which carry the atomizing air and the spray shaping air to theoutlets horizontal bore 74 to avertical bore 76 which has aplug 78 obstructing its upper end, and thence through ahorizontal bore 79, the forward end of which terminates at an O-ring seat 80. As shown in Fig. 5,seat 80 aligns with a similar O-ring seat 82 formed in thehead 6. From this area abore 84 extends forwardly to the atomizingair outlet 22. As shown in Fig. 4, this outlet preferably has an oval shape and it is located centrally between theguide tips - The passages for the spray shaping air can be seen best in Figs. 5, 7 and 8. This air passes sequentially through the
horizontal bore 86, avertical bore 88 which is capped by aplug 90, and a pair ofhorizontal bores nozzle tubes - The wire supply is preferably of the push-pull type wherein the wire comes from a stationary supply which is spaced from the spray gun. As diagrammatically shown in Fig. 1, the wire supply has pusher rolls 97 which engage the
wires wire guiding conduit 99 has its opposite ends affixed to the wire supply and to the gun so that it acts in some respects like a Boden wire system. When the wire feed rolls 97 connected to motor 101 at the wire supply are operated, the wire is pushed forwardly to the feed rolls 14 which pull the wire and deliver it toward the head. The effect of the pusher rolls is to apply compressive forces to the wires within the wire guiding conduits, and also to apply tensile forces to theconduits 99 themselves. The use of pusher rolls reduces the demands on the wire feeding motor in the gun handle, thus making it possible to use a very lightweight motor in the gun. - On the gun, the
wires wire 10 is frictionally engaged between thefeed wheel 14 and anidler wheel 100 which is mounted on a swingingplate 102. Theplate 102 is pivotally mounted on ascrew 104 and it is biased in a clockwise direction by acompression spring 105. The biasing force is adjustable by manually rotating theknurled adjustment knob 106 which is integral with a spring-supportingpin 108 which is threaded into a mountingplate 109 on thebody 2. As will be apparent, rotation of theadjustment knob 106 will change the degree of compression of thespring 105, thus changing the loading force which theidler wheel 100 exerts on thewire 10 to hold the wire against thefeed wheel 14. - The mechanism for driving the
feed wheel 14 and itsright side counterpart 14A is shown in Fig. 6. As previously mentioned, a small electric motor is housed within thehandle 4. This motor rotationally drives avertical shaft 110 which is mounted onball bearing assemblies lower bevel gear 116 and anupper bevel gear 118. - The
left feed wheel 14 is mounted on ashaft 120 which is rotationally supported on a pair ofball bearing units bevel gear 126 with teeth which mesh with the teeth of thelower bevel gear 116 on the motor-drivenshaft 110. Thus, the upper wire-engaging portion of thewheel 14 is rotated in a forward direction to feed the wire through the guide tube and to the fusion area. - The
right feed wheel 14A must also be driven so that its upper wire-engaging surface is moving in a forward direction. Such motion is achieved by mounting thefeed wheel 14A on ashaft 128 which has, at its left end, abevel gear 130 with teeth which mesh with the teeth of theupper bevel gear 118. Theshaft 128 is rotationally supported by theball bearing units shafts - Inasmuch as the
bevel gears feed wheels gears shaft 110, theoppositely extending shafts - The wire-engaging circumferences of the
feed wheels shafts - Although the preceding description has referred to Figs. 1-9 as describing a single embodiment, it will be noted that the gun shown in Fig. 1 differs slightly from the version shown in Figs. 2-9. For example, in the Fig. 1 embodiment, the upper surface of
head 6 has a raised central portion, thebody 2 has an upper surface which is flat except for a raised forward portion, and the swing plate has a rear extension which receives thepivot screw 104. - When a smaller target area is being sprayed or when a smoother finish is desired, the
cone 27,cap 35 and spray-shapingnozzles cone 136 and ashield 137. Air is introduced into the cone from thebores 96 and 96A. The resulting spray strikes a smaller area than the fan shaped spray, and a smoother coating is produced. Thecone 136 has a circumferentially protruding flange at its base which is received in a corresponding recess on the internal surface of thespray shield 137. - As previously mentioned, the invention is particularly advantageous because it provides a relatively small, easily manipulable gun capable of delivering a very high spray rate which, in some instances, can be as much as seven to eight times the spray rate normally achieved with existing lightweight handheld guns. By way of example, a gun made according to the present invention weighs less than 1.25 kg (four and one half pounds). It has a length of approximately 20 cm (eight inches), a height of approximately 21.4 cm (eight and one half inches) including the handle, and a width of about 11.3 cm (four and one half inches). The
conduits cables - Persons familiar with the field of this invention will recognize that it does indeed satisfy the need for a metallizing spray gun capable of a very high spray rate. Additional beneficial features are the convenient and uncomplicated means for feeding the wires and for supplying the head with atomizing air and spray-shaping air.
Claims (8)
- Hand held gun for spraying metal in a forward direction comprising:
a head (6) formed of electrical insulating material,
two electrically conductive guide tubes (16, 16A) which are operable as wire guide means for guiding at least two metal wires (10, 12) lengthwise along two paths which are mutually convergent in a forward direction, while the forward ends of the wires are proximate to each other,
wire feed means (14, 100, 102, 104, 105, 106, 108, 109) for moving the wires forwardly in the wire guide tubes (16, 16a),
electrical circuit means for providing an electrical potential difference between the two wires (10, 12) to form an arc which extends between the two wires (10, 12) to melt the forward ends of the wires in an arc zone, and
directing means (24, 26) for directing a stream of gaseous fluid toward the forward ends (18, 20) of the wires to propel droplets of the molten metal in a forward direction (8), characterized in that
a handle (4) is provided which is grippable by the operator,
the head (6) has a pair of bores (54) extending therethrough,
the wire guide tubes (16, 16A) and wire feed means are arranged to guide and feed the wires (10, 12) in unbent linear paths in the gun, thereby the wire feed means include feed rolls (14, 100) mounted on the gun in proximity of the guide tubes (16, 16A), the feed rolls (14, 100) engage the wires and feed them forwardly in the wire guide tubes (16, 16A) and the feed rolls (14, 100) are rotatable about axes of rotation which are substantially perpendicular to the linear paths of the wires (10, 12) in the gun,
the electrical circuit means include the wire guide tubes (16, 16A) and an electrical connection means which connects an elongated electrical conductor (36, 38) to a connection zone on the wire guide tubes (16, 16A),
the bores (54) in the head (6) have walls which are spaced radially from the tubes (16, 16A) to provide spaces for coolant liquid around the guide tubes (16, 16A), the spaces being located between the connection means and the arc zone,
the spaces have forward ends (40) where the guide tubes (16, 16A) are sealed to the head (6), coolant inlet and outlet openings which are spaced axially in said coolant spaces for admitting coolant fluid to and discharging coolant fluid from said coolant spaces, and
it is provided means for moving a coolant liquid (32, 34, 64) through said coolant spaces, said guide tubes (16, 16A) have external walls which are exposed to the coolant spaces so as to provide for heat transfer from the guide tube (16, 16A) to the coolant liquid. - A spray gun according to claim 1 wherein the electrical circuit means includes two electrically conductive members (50, 50A) which are affixed to said head (6), each of said conductive members having an internal coolant passage which is in communication with one of said spaces for coolant fluid.
- A spray gun according to claim 2 wherein the guide tubes (16, 16A) extend through said conductive members (50, 50A).
- A spray gun according to claim 3 having compression fitting means (60, 62) which are operable to affix said guide tubes (16, 16A) to said conductive members (50, 50A), said compression fitting means being releasable to permit adjustment movement of said guide tubes, said compression fitting means including cap nuts (60) threadedly connected to said conductive members.
- The apparatus of claim 1 including a coolant supply means which is connected to a said coolant inlet opening (64).
- A spray gun according to any one of claims 1-5 wherein the guide tubes (16, 16A) have forward ends (18, 20) which are no more than about 2 cm. from the forward ends of the coolant spaces.
- A spray gun according to any one of claims 1-5 claims wherein said head (6) has a coolant passage (68) which extends between said spaces for coolant fluid.
- A spray gun according to any one of claims 1-5 in combination with a wire supply means which is spaced from the spray gun, said wire supply means including pusher roll means for engaging the wires and driving them toward the gun.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT88906458T ATE94106T1 (en) | 1987-06-25 | 1988-06-24 | METAL SPRAYING DEVICE. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US6617387A | 1987-06-25 | 1987-06-25 | |
US66173 | 1987-06-25 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0371988A1 EP0371988A1 (en) | 1990-06-13 |
EP0371988A4 EP0371988A4 (en) | 1991-10-02 |
EP0371988B1 true EP0371988B1 (en) | 1993-09-08 |
Family
ID=22067728
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP88906458A Expired - Lifetime EP0371988B1 (en) | 1987-06-25 | 1988-06-24 | Metal spraying apparatus |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0371988B1 (en) |
DE (1) | DE3883983T2 (en) |
WO (1) | WO1988010168A1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4042276A1 (en) * | 1990-12-31 | 1992-07-02 | Castolin Sa | DEVICE AND METHOD FOR PRODUCING PROTECTIVE LAYERS |
DE102009031360A1 (en) * | 2009-07-02 | 2011-01-05 | Bayerische Motoren Werke Aktiengesellschaft | Wire conveyor to bring wire to a wire consumer, comprises an excitation device that is arranged so that it directly transfers the wire in oscillation, where the oscillations are transferred from the wire conveyor to the wire |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2749176A (en) * | 1952-09-18 | 1956-06-05 | Arnold Otto Meyer | Electro metal spraying pistol |
LU34348A1 (en) * | 1955-05-02 | |||
US3312566A (en) * | 1962-08-01 | 1967-04-04 | Giannini Scient Corp | Rod-feed torch apparatus and method |
CH607540A5 (en) * | 1976-02-16 | 1978-12-29 | Niklaus Mueller | |
US4508951A (en) * | 1982-08-19 | 1985-04-02 | Richard B. Rehrig | Fluid baffle assembly for a water-cooled welding torch |
US4512513A (en) * | 1982-10-18 | 1985-04-23 | Rogers Frank S | Arc metal spray apparatus and method |
-
1988
- 1988-06-24 EP EP88906458A patent/EP0371988B1/en not_active Expired - Lifetime
- 1988-06-24 WO PCT/US1988/002140 patent/WO1988010168A1/en active IP Right Grant
- 1988-06-24 DE DE88906458T patent/DE3883983T2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
DE3883983T2 (en) | 1994-04-21 |
EP0371988A1 (en) | 1990-06-13 |
EP0371988A4 (en) | 1991-10-02 |
DE3883983D1 (en) | 1993-10-14 |
WO1988010168A1 (en) | 1988-12-29 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0300513B1 (en) | Arc spray system | |
US4937417A (en) | Metal spraying apparatus | |
US4720044A (en) | Electric arc spray metalizing apparatus | |
US6091042A (en) | Arc thermal spray gun extension and gas jet member therefor | |
JP3534435B2 (en) | Plasma spray equipment | |
EP0938932B1 (en) | Arc thermal spray gun and gas cap therefor | |
US5109150A (en) | Open-arc plasma wire spray method and apparatus | |
US6742719B2 (en) | Twin wire electric arc metalizing device | |
US5191186A (en) | Narrow beam arc spray device and method | |
US4853513A (en) | Arc spray gun for coating confined areas | |
US11608553B2 (en) | Wire arc spray swivel head | |
JPS59166263A (en) | Electric arc metal spray device | |
EP0371988B1 (en) | Metal spraying apparatus | |
WO2003090936A1 (en) | Arc spraying torch head | |
US4356971A (en) | Metal spraying apparatus | |
JP3030442B2 (en) | Arc spraying equipment for remote spraying | |
RU2094523C1 (en) | Gear for high-speed electric arc wire deposition by spraying | |
WO1992000160A1 (en) | Narrow beam arc spray device and method | |
RU2014905C1 (en) | Device for electric arc spraying | |
PL153868B1 (en) | Arc metallizing head |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 19900124 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE CH DE FR GB IT LI LU NL SE |
|
A4 | Supplementary search report drawn up and despatched |
Effective date: 19910809 |
|
AK | Designated contracting states |
Kind code of ref document: A4 Designated state(s): AT BE CH DE FR GB IT LI LU NL SE |
|
17Q | First examination report despatched |
Effective date: 19920318 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AT BE CH DE FR GB IT LI LU NL SE |
|
REF | Corresponds to: |
Ref document number: 94106 Country of ref document: AT Date of ref document: 19930915 Kind code of ref document: T |
|
REF | Corresponds to: |
Ref document number: 3883983 Country of ref document: DE Date of ref document: 19931014 |
|
ITF | It: translation for a ep patent filed |
Owner name: JACOBACCI CASETTA & PERANI S.P.A. |
|
ET | Fr: translation filed | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
EPTA | Lu: last paid annual fee | ||
EAL | Se: european patent in force in sweden |
Ref document number: 88906458.0 |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: SE Payment date: 20020625 Year of fee payment: 15 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20020626 Year of fee payment: 15 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: NL Payment date: 20020628 Year of fee payment: 15 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20020702 Year of fee payment: 15 Ref country code: CH Payment date: 20020702 Year of fee payment: 15 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20020709 Year of fee payment: 15 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: AT Payment date: 20020711 Year of fee payment: 15 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: LU Payment date: 20020717 Year of fee payment: 15 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: BE Payment date: 20020821 Year of fee payment: 15 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LU Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20030624 Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20030624 Ref country code: AT Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20030624 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20030625 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LI Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20030630 Ref country code: CH Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20030630 Ref country code: BE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20030630 |
|
BERE | Be: lapsed |
Owner name: *CALL DOUGLAS JR. Effective date: 20030630 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20040101 Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20040101 |
|
EUG | Se: european patent has lapsed | ||
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20030624 |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20040227 |
|
NLV4 | Nl: lapsed or anulled due to non-payment of the annual fee |
Effective date: 20040101 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IT Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED. Effective date: 20050624 |